1. Field of the Invention
The invention relates to a device such as an image recording device for application as a so-called xe2x80x98Digital Still Cameraxe2x80x99 that is often provided with an FT-CCD (Frame Transfer-Charge Coupled Device) and usually requires a real-time preview mode, for example for an electronic viewfinder such as an LCD screen, a display on a television in accordance with the NTSC or PAL standard, or for camera functions such as horizontal and vertical automatic focusing.
2. Description of Related Art
Such an FT-CCD with a storage section of limited size is known, for example, from the international patent application PCT/IB97/01201 (WO 9817051). Although a charge dump is performed with a vertical overflow drain in this known image recording device, and a sampled image is thus transported to the storage section, the speed hereof is in need of improvement, while the further performance of the sensor such as a high maximum charge value Qmax and a high frame shift frequency, must be retained and charge overflow must be avoided.
According to a first aspect of the present invention, which has for its object to obviate the above problems, an image recording device is provided comprising:
an image section with a number of picture elements (pixels) arranged in rows and columns;
a storage section with image storage elements arranged in rows and columns for (temporarily) at least partially storing charge absorbed by the pixels, wherein the charge is transferred to the storage elements, wherein the number of rows in the storage section is fewer than the number of rows in the image section;
characterized in that one or more gates close to the transition between the image section and the storage section are longer than gates more remote from the transition.
According to a further aspect of the present invention, wherein substantially the same problems are obviated, an image recording device is provided comprising:
an image section with a number of picture elements (pixels) arranged in rows and columns;
a storage section with image storage elements arranged in rows and columns for temporarily at least partially storing the charge absorbed by the pixels, characterized in that the charge is transferred to the storage elements;
wherein the doping profile below one or more gates which are close to the transition between the image recording section and the storage section is modified with respect to that below the gates located further away.
As a result of the present invention, the dumping of charge during subsampling is facilitated, i.e. fewer problems occur at high speeds, while a charge overflow between charge packages is also avoided as much as possible at high speeds.